Heater for the coolant liquid of internal-combustion engines



May 26, 1953 J. A. MERRITT HEATER FOR THE COOLANT LIQUID OF INTERNAL-COMBUSTION ENGINES Filed Oct. 26, 1951- 3 Sheets-Sheet l IN V EN TOR. Jack A .lferrz'lz y 26, 1953 J. A. MERRITT 2,640,138

HEATER FOR THE COOLANT LIQUID OF INTERNAL-COMBUSTION ENGINES Filed Oct. 26, 1951 s Sheets-Sheet s {f6 INVENTOR.

J04 A. lye rrz'tt Amyv Patented May 26, 1953 HEATER FOR THE COOLANT LIQUID OF INTERNAL-COMBUSTION ENGINES Jack A. Merritt, Spokane, Wash., assignor to Universal Engine Heater Company,

Spokane,

Wash., a corporation of Washington Application October 26, 1951, Serial No. 253,412

2 Claims. 1

The present invention relates to improvements in a heater for the coolant liquid of internal combustion engines.

In areas where extremely low temperatures are encountered, it is desirable to protect the engines of automobiles, trucks and the like by maintaining the coolant liquid at a temperature that will keep the engine moderately warm. In connection with diesel type engines this is par ticularly necessary because of the difiiculty in getting them to start. It is also of considerable importance in the types of engines commonly used in automobiles and trucks. t is the practice to provide a small heater that is mounted adjacent to the engine and connect it into the coolant liquid circuit of the engine so as to take liquid from a low part of the circuit through the heater and return the liquid to a higher point in the circuit where it will be forced to flow through the engine to get to the low point in the circuit.

The resistance to flow of the coolant liquid through the engine is substantial and oftentimes the normal heating in the heater will not cause enough flow of the coolant liquid from the top of the heater through the engine to the bottom of the heater. It is the principal purpose of my invention to provide a heater for the coolant liquid of internal combustion engines with means for causing the heater to develop an increased flow of the coolant liquid in the nature of a pulsating flow that initially forces a quantity of liquid from the heater through the engine cooling circuit and then takes in a fresh supply of liquid and again heats this fresh supply of liquid to cause another pulsating flow from the heater into the engine cooling circuit.

It is also a purpose of my invention to provide a novel inlet valve device for a heater of the character described, which valve acts as a check valve against reverse flow without completely sealing the liquid inlet to the heater in order to take care of situations where the coolant liquid flowing to the lower inlet of the heater, fails to flow due to loss of heat in the conduit leading to the heater. In the use of certain coolant liquids which have chemicals therein to prevent freezing, the extremely low temperatures sometimes cause such coolant liquids to become viscous or jelly-like so that they do not flow readily. In any system employing an auxiliary heater or" the type to which my invention applies, the coldest spot in the liquid circuit is in the conduit leading from the engine to the heater. The function of the present inlet check valve is to permit limited back seepage of coolant liquid into this inlet conduit in the event there is a tendency of the coolant liquid to J'ell and fail to flow.

My invention also contemplates a novel construction of heater for the purpose described wherein an electrical heating unit is installed in such a fashion that it may be readily removed and replaced and the sealing joint where the heater enters the casing may be made liquid tight.

The nature and advantages of my invention will appear more fully from the following description and the accompanying drawings wherein a preferred form of the invention is shown. The drawings and description are illus trative only, however, and are not intended to limit the invention except insofar as it is limited by the claims.

In the drawings:

Figure 1 is a view in side elevation of a heater embodying my invention;

Figure 2 is a vertical sectional view through the heater;

Figure 3 is a plan view of a heater with the cap that covers the electrical connections removed;

Figure i is an enlarged fragmentary sectional view taken on the line 44 of Figure 2;

Figure 5 is a fragmentary sectional view taken on the line 55 of Figure 2;

Figure 6 is a perspective view on a reduced scale of the electrical heating element shown in connection with the heater; and

Figure 7 is a face view of the valve employed as a check valve at the inlet of the heater.

Referring now in detail to the drawings, my invention is embodied in a heater of the character described wherein a heater casing is composed of an upper section ill having an outlet nipple II and a lower section !2 having an inlet boss 13. The two casings sections are constructed to overlap at their meeting ends as indicated at I4. A sealing gasket I5 is inserted between the two sections Ill and I2. In order to secure the sections together, the upper section [0 has a rod [6 cast therein by means of a boss H. The rod It has its lower end threaded at I8 and the lower casing section 12 has an aperture I9 to receive the rod 15. A gasket 2%, a washer 2i and a nut 22 serve to seal the opening ['9 and to clamp the two sections l0 and I2 together.

The upper section iii of the casing has a mounting plate 23 cast integral therewith. It also has a supporting rib 24 and two bosses 25 and 26 formed on the top thereof. The rib 24 and the two bosses 25 and 26 serve to support an inverted cup shaped cover 21 on the top of the section in such a way that air may circulate between the top of the section III and the cover. The cover has an internal shoulder 28 that rests on the rib 24 and the outer edges of the bosses and 26. The rod 16 extends upwardly through the cover 27 and is threaded at 29 to receive a nut 30.

Internal bosses 3| and 32 extend downwardly into the heater section 10 opposite the bosses 25 and 26. As shown best by Figure 4 of the drawings, the bosses 25-3! and 26-32 are internally threaded to receive sleeve nuts 33 and 34. A heater element 35 has its ends extending upwardly through the bosses for connection to wiring terminals 36 and 31 that supply current to the heater 35. Within each of the bosses 253l and 2S-32 the opening for the sleeve nut extends down far enough to receive a lead ring 38 which seats on a shoulder 39. The

parts of the heater 35 which extend through the bosses are roughened as indicated at 40 in Figure 4. In order to obtain a water tight seal, it is only necessary to turn down the sleeve nuts 33 and 34 which are bevelled at their lower ends as indicated at M. The pressure of the sleeve nut on the lead ring 38 collapses the ring and forces it into Water tight engagement with the knurled surface of the heater and with the shoulder 39. When it is desired to remove the heater, the sleeve nuts 32 and 34 are loosened and the heater can then be tapped lightly to drive the knurled portions 40 through the lead rings 38. The heater can be replaced and sealed again by further tightening of the sleeve nuts to further compress the rings.

The inlet boss i3 is threaded to receive a valve unit 42, which has a nipple 43 for attaching an inlet conduit. The valve unit 42 has a recess 44 to receive a check valve 45 that is held against removal by a spider 46. The spider48 'fits close enough to the check valve to prevent it from tipping out of position but allows it to open and let liquid in through the nipple .43. The construction of the valve 45 is important to my invention. As shown best by Figures 2, -5

and '7, the valve 45 is made of a thin sheet of metal, normally circular, that is cupped by striking it in the center with a polygonal tool so that the three sides 45a, 45b and 45a are bent at an angle to the base portion 45d. When the valve is formed in this fashion, it leaves narrow portions indicated at 45c, raised slightly with respect to the edges of the intervening portions 45a, 45b and 450 so that the valve does not seat solidly against a flat valve seat. This is illustrated best in Figure 2 of the drawings where the space between the portions 45c and the valve seat can be seen.

It will be observed'from an inspection of Fig ure 2 that the outlet opening I l is spaced a short distance below the top wall Illa of the casing section it. The amount is slight but it leaves a small pocket 41 above the top of the opening to the nipple l i. In the operation of the heater,

the pocket 41 cooperates with the valve 45 in.

causing the liquid to flow through the heater as it is heated up with a pulsating action. The valve 45 prevents back circulation throughthe inlet 43, however, since it does not solidly seat over-the inlet opening when the coolant liquid.

the pocket 41.

4 in the heater is heated, there will be a limited amount of leakage back into the nipple 43. This is particularly useful in the event that the coolant liquid is of a type that becomes viscous or jelly-like when it gets too cool.

The casing construction whereby the two casing sections ll and I2 are fastened together is quite convenient for installation. The usual installation is to have the casing vertical with the inlet nipple 43 directly below the outlet nipple vll. However, the lower section 12 can be turned on the rod 16 to direct the inlet nipple 43 in the most convenient direction for the attachment ,of an inlet conduit thereto. The nut 22 is then tightened to clamp the sections together. The heatercasing can be installed with the inlet nipple 43 and the outlet nipple ll pointing in the same direction, or in opposite directions, or in any position between these two positions. The only precaution necessary is to keep the outlet nipple H uppermost so that the heated liquid rises to it.

In the operation of the heater, the coolant liquid fills the two sections l0 and I2 and there is a certain amount of gas or air entrapped in As the liquid is heated up in the heater, it gives up a certain amount of its absorbed gases and it also expands. The pocket .41 traps the gases and initially the liquid expansion will compress the gases in the pocket 47 until eventually the pressure in the heater is suiiicient to force liquid into the circulating system of the internal combustion engine to which the heater is attached. When the liquid starts to flow, the compressed gases in the pocket 41 forces more of the liquid out through the pple H and some of the gas escapes through the nipple. When there is an escape of gas, the drop of pressure in the heater is quite sudden and this causes the valve 45 to open, admitting a quantity of coolant liquid into the theater. This relatively cold coolant liquidcauses the pressure in the heater to drop temporarily and more liquid will flow into the heater past the valve 44. The liquid starts to warm up immediately after it enters the heater and expands .until the back pressure is sufficient to close the valve 45 again. The temperature drop in the heater due to the in-rush of liquid, reduces the pressure of gas in the pocket 41 temporarily. Thereafter the heating up of the liquid in the heater again forces more gas into the pocket 41 and compresses the gas in this pocket untilade- 'quate pressure is reached in the heater to force more liquid out throughthe nipple II. In this way the heater produces a pulsatingfiow of the coolant liquid through the cooling system of the internal combustion engine.

It is believed that the nature and advantages of my invention will be clear from the foregoing description. Having thus described my invention, I claim:

1. A heater for the coolant liquid of internal combustion engines comprising a vertically ex- .surface ofthe casing to trap a small quantity of gas in the casing above the outlet, said inlet having a fiat seat for said .valve and the valve comprising a circular sheet cupped to present a concave face toward the inlet, the rim of said sheet being" deformed to provide leak passages between the rim and said. seat when the rim is held against the seat.

2. A heater for the coolant liquid of internal combustion engines comprising a liquid tight casing, heating means in the casing, a liquid inlet to the lower portion of the casing, a check valve in said inlet operable to substantially close said inlet to liquid flow from the casing, a liquid outlet from the upper portion of the casing, said inlet having a flat seat for said valve and the valve comprising a circular sheet cupped to present a concave face toward the inlet, the rim of said sheet being deformed to provide leak pas- 6 sages between the rim and said seat when the rim is held against the seat.

JACK A. MERRITT.

References Cited in the file of this patent UNITED STATES PATENTS 

